Portable trolley system



Oct. 3, 1967 R, J. KILBURG PORTABLE TROLLEY SYSTEM 4 Sheets-Sheet 1Filed April 2'7, 1964 Oct. 3, 1967 I R. J. KILBURG 3,345,471

PORTABLE TROLLEY SYSTEM Filed April 27, 1964 4 Sheets-Sheet 2iffd/FA/EKS? Oct. 3, 1967 R. J. KILBURG 3,345,471

PORTABLE TROLLEY SYSTEM Filed April 27, 1964 4 Sheets-Sheet 3 drum/5mOct. 3, 1967 Filed April 27, 1964 R. JIKILBURG 3,345,471

. PORTABLE TROLLEY SYSTEM 4 Sheets-$heet 4 "'I II 1 I I I I I! I I I I lI I I l II IIII INVENTOR. paw/0 J/Wlflf United States Patent forniaFiled Apr. 27, 1964, Ser. No. 362,730 Claims. (Cl. 191-45) Thisinvention relates to mobile electrification systems, and moreparticularly to a system for supplying power to portable hand tools.

In many industrial operations, it is necessary to provide a source ofpower for portable hand tools that are used by the workers at differentpositions along an assembly line or in different parts of a work area.Conventional wiring and outlets at the different locations is onesolution, but it not only requires a.lot of lost motion by the workersin plugging and unplugging the power cords of the hand tools, butcreates safety problems due to the indiscriminate draping of power cordsalong the floor in the work area. These disadvantages, among others,have led many plants to utilize overhead electrification systems.

These overhead electrification systems are normally mounted above theassembly line or over the work area within easy reach of the workers. Asa result, the conductors or bus bars are normally supported in aprotective housing-one having a minimum opening-to prevent a worker fromaccidentally touching the current carrying conductors. The hand toolsare electricalb co nnected to movable trolleys which are supportedinside the housing for movement along the line of the overhead system.Such systems have the advantage of getting the power lines off of thefloor and allowing the tools to be moved along the assembly line oraround a work area without plugging and unplugging them all the time. Inmany cases, a support for the hand tool, when it is not being used, isconnected to the trolley as well.

In spite of the many advantages that movable trolleys provide, however,those currently available have certain shortcomings. Since the conductorhousing must be finger proof, cover plates or drop-out sections in thehousing must be provided to get the captive trolley inside the housing,or the required number of trolleys must be placed in the housing when itis assembled. This may not be too inconvenient as long as each hand toolis used along the same part of an assembly line or in the same sectionof a work area, but often it is most efficient if a worker can passother workers and plug in a hand tool anywhere along the electrificationsystem. If this is required, drop-out sections must be judiciouslyprovided or, the tool unplugged from the trolley and transferred toanother trolley. Whenever this is done, many of the disadvantages thatare attributable to conventional wiring outlets are re-introduced. 5

Over and above these restrictions on flexibility created by many priorart systems, captive trolleys mounted inside of protective housing havecertain technical drawbacks. In the first place, space is at a premiumin most plants so that the protecting housings must be reasonably small.It follows that the trolleys and their mounting wheels must also besmall. Small wheels are far more susceptible to jamming and theaccumulation of dirt and grease on the supporting tracks takes its toll.

Secondly, this difliculty is compounded since the housing is difficultto clean when it is worker safe. When obstructions occur, it is usuallynecessary to shut down the electrification system and partiallydismantle the housing. Also, inability to visually or physically examinethe guide rail area inside the housing to determine the cause of thejamming is no small part of the problem.

The present invention is designed to ameliorate some 3,345,471 PatentedOct. 3, 1967 "ice of these shortcomings, and to do so, by providing aportable trolley system that is flexible, safe, rugged and economical.Generally speaking, this novel portable trolley system realizes a numberof advantages over prior systems by placing the guide rails on theoutside of the housing, by increasing the size of the supporting wheelssubstantially, by providing auxiliary wheels which, among other things,stabilize the trolley as it is moved along the rails, by incorporatingmeans in the trolley to enlarge the spacing between the guide wheels sothey can clear the rails when the trolley is mounted on the housing, andproviding a novel collector shoe assembly.

The over and under wheel arrangement of the present portable trolley andthe outer rail offer a number of advantages. The external rails areeasier to maintain and clean. Moreover, when dirt and grease orobstructions cause problems, it is easy to see precisely where thetrouble is so that the situation can be remedied in a minimum amount oftime. Furthermore, such cleaning and repair can be done without shuttingdown the electrification system or otherwise completely interrupting theoperation of the assembly line or work area.

The use of larger wheels in and of itself constitute a substantialbenefit over the prior art system inasmuch asthe larger at supportingwheel is, the less likely it will be to be jammed by dirt or greasedeposited along the guide rails or between the wheels. Also, the use ofa single, relatively large wheel on each side of the portable trolley tocooperate with auxiliary wheels mounted on the trolley body just beneaththe tracks or flanges has added advantages. It has been found to begenerally superior to the conventional four-Wheel support systemsbecause the single point of support for the trolley means, that when atrolley is pulled in eitherdirection, the stabilizing wheels away fromthe direction of pull, and those only, cooperate with the guide orsupport wheels to rotate the trolley downwardly so that it moves alongits track easily. The other auxiliary wheels do not engage the railwhich reduces the forces opposing the movement of the trolley.

Other advantages also result. The over and under wheel arrangement isdesirable because the fore and aft wheels are closely juxtaposed to bothsurfaces of the rail which provides substantial reinforcement for it sothat the rail will not be deformed or pulled out of shape. An ancillarybenefit of the open type housing with outwardly projecting flanges alsoarises because it permits the housing to be reinforced interiorly bystruts if needed to support relatively heavy hand tools. In the case ofmost prior art trolley systems, the trolley support mechanism, ofnecessity, had to be so small and took up such a large percentage of theinterior of the housing that it left little room to reinforce thehousing when the need arose. With the present arrangement, except forthe spaced apart conductor bars and their supporting brackets, there isnothing in the housings interior to interfere with reinforcing struts.Yet another advantage of the outer track arrangement is that the supportpoints for the portable trolleys are at maximum outward locations whichprovides better stability for the trolley as it is pulled along thetrack.

To eliminate the need for drop out sections or substantiallydisassembling the housing whenever a portable trolley is to be mountedtherein, the trolley includes means to move the guide wheels outwardlyfrom their normal position so they can clear the edge of the flangeforming the supporting tracks. By this means, it is possible to mountand demount the portable trolley at any point along the overheadelectrification system without using any special dropout sections. Theassignee of the present application has had occasion in the past to workon the development of portable trolleys which eliminate the need 3 fordropout sections. But one of the difiiculties, where the trolley iscaptured inside the housing, is the limited space in the housing. Alsoit does not meet the other needs of a truly versatile portable trolleysystem.

One of'the things that makes the present system particularlyadvantageous is the use of insulated conductor bars of the so-calledO-bar or figure 8 type wherein each conductor bar is insulated exceptfor an open slot along its lower edge. The uninsulated slot in theinsulated conductorbars is too narrow to permit a workers finger totouch the bare conductors. This makes the conductor bars entirely safeand eliminates the need for the substantially closed housing heretoforeemployed.

Moreover, by using a plurality of parallel conductor bars supported inthe housing and vertically oriented colle-ctor shoes in the trolley, itis possible to provide a flexible system adapted to connect one, two, orthree or more electrical circuits to portable hand tools associated witha portable trolley. In most prior art systems, the conductor bars arearranged interior of the housing in a Y-configuration which makes itdiflicult to provide more than three connections to the portabletrolley. A feature related to the use of collector shoes supported invertical array on the trolley body is the non-symmetrical transversespacing of the conductor bars and collector shoes so that the portabletrolley has to be polarized to fit onto the housing. This assures thatthe right collector shoes contact the right conductor bars.

Another feature of the present invention pertains to the removablecollector shoes vertically supported along the upper part of the body ofthe trolley and adapted to slidably engage the conductor bars when thetrolley is mounted on the housing flange. These collector shoes areeasily removed when they become Worn. They can be replaced easilywithout requiring a shut down of the entire electrification system orwithout interrupting the operation of the assembly line.

In one of its broader recitations, the present invention provides aportable trolley for supplying power to hand tools from overheadconductors which are mounted along a path defined by a pair ofcontinuous support rails that combines a body member, a plurality ofcollector shoes carried by the body to slidably engage the overheadconductors when the trolley is supported along the rails, support armsconnected to the body, guide wheels rotatably mounted on the arms toengage the rails to support the body adjacent the overhead conductors,auxiliary wheels rotatably mounted on each side of the body with theguide wheels disposed between them and means operable to mount thetrolley so that the guide wheels ride on the rails and the auxiliaryWheels are disposed below the rails.

More specifically, the invention is a system for supplying power toportable hand tools that includes a pair of spaced-apart tracks, aplurality of current conductor bars insulatedly supported intermeditaethe tracks at spaced intervals and a removable carriage supported on thetracks to transfer current from the conductor bars to the tools. Theremovable carriage includes a body member, a plurality of collectorshoes supported in the top of the body at spaced intervals correspondingto those of conductor bars, a pair of outwardly and upwardly extendingarms normally supported by the body in a closed position, relativelylarge guide wheels rotatably mounted on the outer ends of the arms toride on the upper surfaces of the track when the arms are in the closedposition, pairs of auxiliary wheels rotatably mounted on both sides ofthe body with the guide wheels between them, and means to change thetransverse spacing of the guide wheels so that the carriage can befreely mounted on the tracks with the arms in their closed position.

These and other objects, advantages and features of the presentinvention may be more fully understood when the following detaileddescription is read with reference to the drawings in which:

FIG. 1 is a parital perspecitve of an exemplary assembly line with anumber of portable trolleys constructed in accordance with the presentinvention supported therealong;

FIG. 2 is a perspective of a part of a portable trolley system inaccordance with the present invention;

FIG. 3 is an end view of the portable trolley suspended on the housingand cooperating with the conductor bars with certain parts broken awayto more clearly show its construction;

FIG. 4 is a section taken along line 4-4 of FIG. 3 to illustrate thecollector shoe assembly;

FIG. 5 is a side view of the portable trolley mounted on a housing;

FIG. 6 is an end view of the'outwardly projecting hanger arms of theportable trolley with certain parts broken away to illustrate how themechanical linkage controlling the arms is constructed and with theoutermost position of the guide wheels shown by dotted lines;

FIG. 7a is a section taken along line 77 of FIG. 6 to illustrate themechanical linkage when the arms are in their normal or closed position;

FIG. 7b is a section taken along 77 of FIG. 6 but with the mechanicallinkage extended as it is when the arms are in their open or mountingposition; and

FIG. 8 is an enlarged partially exploded view of the means to lock anarm either in its closed or mounting position.

The portable trolley system forming the present invention is illustratedadjacent an assembly line in FIG. 1. Housing 10 supports a plurality ofportable trolleys or carriages 15 at spaced apart points. Suspended fromthe trolleys 15 by power cords 16 are various hand tools, illustratedgenerally at 17. It can be seen that the housing 10 is supported alongand above an assembly line or work bench 18.

Looking more particularly to FIGS. 2-5, the cooperat ing parts of theportable trolley system can be readily appreciated. A plurality ofconductor bars 13 are supported in spaced apart parallel relationinterior of the housing 10. The housing 10 is formed of two pieces ofsteel to approximate an inverted open box with outwardly projectingflanges or hems 21. The two parts of the housing 10a and 10b are weldedor otherwise affixed at surfaces 22 and the housing is connected tooverhead support brackets (not shown) by the upper flange 23.

The conductor bars 13 can be the so-called 0 type conductor barsillustrated in FIG. 2 or the figure-8 conductorbars illustrated in FIG.3. In both cases, they include a conductor bar 26 having an insulatedsheath 27 therea-round with an opening along the lower edge of theconductor bars to permit the collector shoes 64 on the portable trolleyto contact the conductor bars 26 to transfer power to a hand tool bypower cord 16. In some cases, it may be desirable to use uninsulatedconductors and insulated hanger clamps, but for maximum safety,insulated conductor bars are to be preferred.

As illustrated particularly in FIG. 3, the insulated conductor bars 13are supported in parallel array by plurality of supporting hangers 32which are aflixed to a transverse bracket 33 that is attached to theinside of housing 10.

In the case of both types of conductor bars illustrated in the drawings,the center conductor bar is closer to the one on the left than to theone on the right (with respect to FIGS. 1 and 3). This non-uniformity inthe spacing of the conductor bars 13 is to provide a positivepolarization of the portable trolley with respect to the conductor barsso that the trolley can only be attached when it is properly oriented.

The portable trolley 15 generally includes a body 41 having two parts,41a and 41b, which are held together by screw members such as 42; anumber of collector shoe assemblies 61; auxiliary wheels 44; guidewheels 50; and hanger arms 48.

The spaced apart auxiliary wheels 44a and 4412 are rotatably supportedon each side of the body member 41, and each has an outwardly disposedshoulder 45 which rides adjacent the edge of its rail 21 when theportable trolley is mounted on the housing 10. These wheels 44 provide astabilizing function for the portable trolley 15 as it is moved alongthe rails. The auxiliary wheels 44 also act as a stop for upwardmovement of the body member 41 when the trolly is mounted or demountedas hereinafter explained.

The outwardly and upwardly projecting hanger arms 48 have guidewheels'50 rotatably supported on their uppermost ends. Each guide wheel50 has an outwardly disposed shoulder 51. In its operatingor closedposition.

(illustrated in FIGS 1 and 3), the guide wheels 50 ride on the uppersurfaces of the rails 21 and the projecting shoulders 51 are adjacentthe outer edge of their rails 21.

It will also be observed that the arms 48 dispose the guide wheels 50longitudinally between the auxiliary wheels 44a and 44b. This offset andover and under wheel arrangement gives excellent results. As mentionedearlier, if the trolley 15 is to be pulled, say to the right of the FIG.2 drawing, the right side of the trolley 15 is pulled away from the rail21 and only auxiliary wheels 44a cooperate with the guide wheels 50 tostabilize the trolley. The wheels 44b do not contact the bottom of therail 21 at all. The .trolley 15 is canted or tilted forward which placesthe force of the pull on the guide wheel. The forward auxiliary wheels4411 in a left to right pull do not impede the movement of the trolley.By the same token, if the trolley is to .be moved from the right to theleft of FIG. 2, the auxiliary wheels 44a do not engage the lower part ofthe rails 21 and the trolley is moved under the control of guide wheels50 and auxiliary wheels 44b.

A plurality of collector shoe assemblies 61 (FIGS. 3 and 4) are disposedin slots 62 formed longitudinally in the body 41. Each collector shoeassembly 61 includes the rectangular collector shoe 64 supported in agenerally U-shaped holder 66 that has a lower plate 67 and a pair ofupstanding sides 68. The sides include a neckeddown portion 69 whichengages grooves 71 formed on the longitudinal sides of its collectorshoe 64. Each plate 67 of the holder 66 has spaced apart depending pins72 which act as guides for compressed helical springs 73 which aremounted between the lower surface of plate 67 and the lower surface 74defining the slot 62. The springs 73 urge a holder 66 upwardly to forcethe contacting surface 65 of the collector shoe 64 against the loweredge of the conductor bar 26. Electrical connections between the holder66 and the insulated power cord 16 are also provided.

Turning to the means by which the arms 48 are connected in t-hebody 41and moved outwardly, the rectangular shaped arms 48 fit into slots 81formed in the lower part of the body member 41. They are connected byway of links 82 and 83 to a drive link'84 which is, in turn, staked to avertical shaft 86 rotatably mounted in body 41. A handle 87 is connectedat the lower end of shaft 86. A rectangular tension plate 91, aflixed tothe shaft 86 (by means not shown), and a washer-type spring 94 isinterposed between the tension plate 91 and the lower surface 96 of thebody member to urge the plate 91, the handle 87 and the shaft 86 toremain in a downward position.

The inner ends of the arms 48 have radially oriented parallel slots 101formed through them which terminate in recessedcircular shoulders 102.Upstanding parallel sided pins 92 are disposed in the slots 101 and areaflixed at their lower ends to plate 91. The pins terminate in circularshoulders 103, the diameters of which-coincide with the diameters ofrecessed shoulders 102. With this arrangement, whenever the shaft 86 isin its closed or open position, the circular shoulders 103 move into therecessed shoulders 102 under the force of spring 94 to 6 lock the arms48 in their instant positions. Only by pushing upwardly (with respect tothe orientation of FIG. 2 for example) on the handle 87 and itsassociated shaft 86 is it possible to move the circular shoulders 103out of their recesses 102. At this point, the shaft 36 can be rotated tocause link 84 to move the driven links 82 in translation from oneposition to another. For example, if the guide Wheels are in openposistion, then the arms 48 can be rotated to their closed position orvice versa.

In the mounting operation, the portable trolley 15 having a hand tool 17connected to it by way of power cord 16 is located beneath the housing10 with the auxiliary wheels 44 resting against the underside of therails 21. With the auxiliary wheels 44 preventing the body member 41from moving too far towards the housing, the handle 87 is moved upwardlyto release the shoulders 103 from the recesses 102. Thereafter, thehandle 87 and shaft 86 are rotated to move the arms 48 to their closedor normal position, which position places the guide wheels 50 on theupper surfaces of the guide rail 21. Release of the upward pressure onthe handle 87 allows the shoulders 103 to fall into the inwardlydisposed recesses 102. This locks the portable trolley 15 firmly inplace on the housing 10.

As a worker utilizes a connected hand tool along an assembly line, hepulls the portable carriage along with him.

At the end of the assembly line, or anywhere along it, the worker canreverse the process involved in mounting the trolley on the housing toremove it. He pushes upwardly on the handle 87 to unlock the shaft 86which controls the movement of arms 48 and guide wheels 50 attachedthereto. Rotation of the shaft 86 thereafter moves the arm 48 outwardlyso that the guide Wheels 50 clear the edges of the rails 21. Theportable trolley 15 can then be removed and carried with the hand toolto another point on the assembly line and there re-attached to thehousing to provide power for the hand tool as work is continued.

While the invention has been described with respect to an exemplaryembodiment, it should be apparent to those skilled in the art thatchanges can be made in the basic concept without departing from thespirit and scope of the invention. For this reason the invention shouldbe limited only to the extent of the claims.

What is claimed is:

1. A portable trolley for supplying power to hand tools from overheadconductors mounted along a path defined by a pair of continuous supportrails comprising, in combination,

abody;

a plurality of collector shoes carried by said body to slidably engagethe ovehead conductors when the trolley is supported on said rails;

movable support arms mounted on said body;

guide wheels rotatably mounted on said arms to engage the rails tosupport said body adjacent the overhead conductors;

auxiliary wheels rotatably mounted on each side of said body with theguide wheels therebetween to stabilize the body by selectively engagingthe underside of said pails when the portable trolley is mounted -onsaid rails; and

means operable to extend said arms transverse to the axis of the railsso as to mount the trolley so that the guide wheels ride on said rails.

2. A portable trolley in accordance with claim 1 wherein the spacingsbetween the overhead conductors and the cooperating collector shoes arenon-symmetrical to assure correct polarization of the collector shoecircuits and including means associated with the mounting means andinterior of said body to lock said arms when the trolley is mounted onthe support rails for movement therealong.

tion of said shaft to change the separation between said guide wheels bymoving said arms;

said shaft normally occupying an axial position in which the rotation ofthe shaft is blocked; and

a carrying handle connected to said shaft so that said shaft can bemoved axially to free it for rotation and then rotated to position saidarms.

4. A system for supplying electrical power to hand tools used along amoving assembly line comprising, in combination,

a housing having uninterrupted flanges extending outwardly from itssides supported adjacent an assembly line;

a plurality of conductor bars insulated except for their lower edgessupported in nonsymmetrical relation interior of said housing; and

a portable carriage adapted to be moved along said housing;

said carriage including an insulated body;

a hanger attached to said body;

guide wheels having shoulders rotatably mounted on the one end of saidhanger to support said body on said flanges and prevent movementtransverse to said flanges;

a pair of stabilizing wheels symmetric-ally mounted fore andaft of saidguide wheels to lie just below the bottom of the flanges when the bodyis sup ported adjacent said housing by said hanger;

means manually operable to move said guide wheels outwardly intranslation to clear said flanges when the carriage is to be attached tosaid housing or removed therefrom;

means enclosed in said body and cooperating therewith to lock saidhanger and said guide wheels in their innermost positions after saidcarriage is mounted on said housing; and

a plurality of vertically oriented collector shoes supported interior ofsaid body to slidably engage the uninsulated edges of said conductorbars.

5. In a system for supplying power to portable hand tools that includesa pair of spaced apart tracks, a plur ality of current conductor barsinsulatedly supported intermediate said tracks at spaced intervals and amovable carriage supported on the tracks to transfer current from theconductor bars to the tools, the improvement in the removable carriagecomprising, in combination,

a body member;

a plurality of collector shoes supported adjacent the top of said bodyin parallel relation and at spaced intervals corresponding to those ofthe conductor bars;

a pair of outwardly projecting arms normally supported by said body inpreselected spaced apart relation;

guide Wheels rotatably mounted on the outer ends of said arms to ride onthe upper surfaces of said tracks when said arms are in said preselectedspaced apart relation;

a pair of auxiliary wheels rotatably mounted on both sides of said bodywith the guide wheels therebetween; and,

means associated with said body member operable to move the projectingarms in translation to change the spacing between said guide wheelstransverse to said tracks so that the carriage can be mounted on saidtracks.

6. A portable hand tool carriage in accordance with claim 5 wherein saidguide Wheels are relatively large in comparison with said auxiliarywheels and said g auxiliary wheels underlie a substantial transversepart of the lower surface of said tracks when the carriage is supportedon said housing and are normally just below the lower surface of saidtracks to assist in stabilizing the carriage during movement and to actas a stop to upward movement of said body with respect to said trackwhenever the body is mounted or demounted from the tracks.

7. A portable hand tool carriage in accordance with claim 5 wherein saidmeans operable to change the transverse spacing of said guide wheelscomprises an axially movable shaft having a handle attached theretorotatably supported in said body;

a first link aflixed to saidshaft;

a pair of links pivot-ally connected at one set of their ends to saidfirst link on opposite sides of said shaft and at their other ends tothe inner ends of said projecting arms so that rotation of said shaftmoves projecting arms between inwardly and outwardly positions;

transverse slots formed in each of said projecting arms which terminatein circular recesses;

a plate underlying said arms and aflixed to said shaft;

said plate having affixed to it on opposite sides of said shaft spacedapart, upstanding guide pins with circular shoulders at their upperends, said pins projecting through said slots;

resilient means normally holding said plate away from said body,

the circular shoulders on said pins seating in said recesses to locksaid shaft against rotation when said plate is away from said body; and

means to move said plate and shaft axially upward to free said shouldersfrom one set of said circular terminations so that said shaft can berotated with the pins moving along said slots to positions overlying theother circular recesses;

said circular shoulders responsive to said resilient means to move intosaid recesses upon release of said plate.

8. In a system for supplying power to portable hand tools that comprisesan inverted open housing having outwardly projecting hems on each of itssides, a plurality of conductor bars insulatedly supported in spacedparallel relation within the housing and a carriage movably suspendedfrom the housing to permit the transfer of current from the conductorbars to the tools as the carriage is moved along the housing, thecarriage comprising, in combination,

an insulated body member having a longitudinal axis parallel to theconductor bars and the supporting hems of the housing when the carriageis mounted on said housing;

a plurality ofremovable collector shoes;

means supporting said collector shoes in the top of said body in planesparallel to said axis and at transverse intervals corresponding to theseparation between said conductor bars;

a pair of hanger arms connected to said body member for translationalmovement in a transverse plane between a normal position and anattachment position;

guide wheels rotatably mounted on the ends of said projecting arms toengage the upper surfaces of said hems when said arms are in said normalposition;

auxiliary wheels rotatably mounted on said body member fore and aft ofeach of said guide wheels to underlie said hems when said carriage ismounted on said housing; and

means generally interior of said body member operable to move said armsoutwardly to said attachment position so that said guide wheels canclear the outer edges of said hems before being moved inwardly to saidnormal position to mount said carriage o a d housin 9. A portable handtool carriage in accordance with claim 8 wherein means are operative tolock said arms in said normal and attachment positions,

said body member is formed in two parts;

said supporting means for the collector shoes are disposed inlongitudinal slots formed in the two halves of said body member beforeit is assembled;

each of the collector shoe supports includes an elongated U-shapedholder having a restricted longitudinal neck portion and resilient meanscooperating with said body member to urge said holder toward the upperpart of said carriage, and

said collector shoes are generally rectangularly shaped withlongitudinal grooves formed in their sides for their retention by thereduced neck portions of their respective support holders and saidauxiliary wheels act as a stop for said body member to avoid damage tothe collector shoes and supports and so that the means to move said armscan be moved upward with respect to said body member to unlock saidarms.

10. In a system for supplying power to portable hand tools that includesan inverted open housing having outwardly projecting flanges on each ofits sides, a plurality of figure-8 conductor bars insulated except fortheir lower edges supported in non-uniform spaced parallel relationWithin the housing and a carriage having a hand tool electricallyconnected to it removably suspended from the housing to permit thetransfer of current from the conductor bars to the electrical connectorfor the tool as the carriage is moved along the housing, the improvementin the portable carriage comprising, in combination,

an insulated body member having a longitudinal axis;

a plurality of collector shoes confined in the upper part of said bodymember to slidably engage respective ones of said conductor bars whensaid carriage is mounted on the overhead housing with the longitudinalaxis of its body parallel to the lay of the conductor bars;

two stabilizing wheels having outer shoulders rotatably mounted on eachside of said body member to underlie said flanges when the carriage issupported on said housing;

a pair of arms extending outwardly from said body member intermediatethe stabilizing wheels on each side of said body member for transversemovement between a normal position and a mounting position;

relatively large guide wheels having outer shoulders rotatably mountedon the outer ends of said arms to ride on the upper surfaces of saidflanges when said arms are in said normal position and to be spacedapart a distance greater than that between the outer edges of saidflanges when said arms are in said mounting position;

control means manually operable to move said arms to said mountingposition so that the guide wheels can pass by said flanges and to saidnormal position in which said guide wheels engage said flanges;

said control means including a shaft rotatably mounted in the lower partof said body member and having a handle atfixed to its lower end and amechanical linkage responsive to the rotation of said handle and saidshaft to move said arms between said mounting and normal positions;

means to lock said shaft in either one of said normal and mountingpositions; and

means associated with said arms responsive to the axial movement of saidshaft to release said locking means so the shaft can be rotated betweensaid positions.

References Cited UNITED STATES PATENTS Re. 19,513 4/1935 Frank et al.191-23 2,117,480 5/1938 Harvey 191-45 X 2,170,298 8/1939 Frank 191-45 X2,645,187 7/ 1953 Guadagna. 2,696,532 12/1954 Herrmann et al. l9156 X2,830,136 4/1958 Herrmann et'al. 2 19145 X 2,830,137 4/1958 Herrmann etal. 191-45 X 2,912,526 11/1959 Herrmann et al. 191-23 3,017,958 1/1962Richter 2- 19l150 X 3,206,560 9/1965 Parmenter.

ARTHUR L. LA POINT, Primary Examiner.

S. T. KRAWCZEWICZ, Assistant Examiner.

1. A PORTABLE TROLLEY FOR SUPPLYING POWER TO HAND TOOLS FROM OVERHEADCONDUCTORS MOUNTED ALONG A PATH DEFINED BY A PAIR OF CONTINUOUS SUPPORTRAILS COMPRISING, IN COMBINATION, A BODY; A PLURALITY OF COLLECTOR SHOESCARRIED BY SAID BODY TO SLIDABLY ENGAGE THE OVERHEAD CONDUCTORS WHEN THETROLLEY IS SUPPORTED ON SAID RAILS; MOVABLE SUPPORT ARMS MOUNTED ON SAIDBODY; GUIDE WHEELS ROTATABLY MOUNTED ON SAID ARMS TO ENGAGE THE RAILS TOSUPPORT SAID BODY ADJACENT THE OVERHEAD CONDUCTORS; AUXILIARY WHEELSROTATABLY MOUNTED ON EACH SIDE OF SAID BODY WITH THE GUIDE WHEELSTHEREBETWEEN TO STABILIZE THE BODY BY SELECTIVELY ENGAGING THE UNDERSIDEOF SAID RAILS WHEN THE PORTABLE TROLLEY IS MOUNTED ON SAID RAILS; AND